Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
Case	Tag   Price	Sales   Tax %	Raw Total   Incl. Sales Tax	Rounded   to Penny	Rounded   to Nickel	Rounded   to Dime
Purchase #1	$182.55	7.405%	$196.0678	$196.07	$196.05	$196.10
Purchase #2	$209.80	7.729%	$226.0154	$226.02	$226.00	$226.00
Purchase #3	$134.39	10.444%	$148.4257	$148.43	$148.45	$148.40
Purchase #4	$43.33	6.175%	$46.0056	$46.01	$46.00	$46.00
Purchase #5	$58.77	7.113%	$62.9503	$62.95	$62.95	$63.00
Purchase #6	$88.75	12.230%	$99.6041	$99.60	$99.60	$99.60
Purchase #7	$99.73	5.397%	$105.1124	$105.11	$105.10	$105.10
7 purchase totals =	$817.32		$884.1813	$884.19	$884.15	$884.20